Reaction SMILES: [NH2:1][C@@H:2]([CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[C@H:3]([OH:7])[C:4]([OH:6])=[O:5].CCN(CC)CC.Cl[C:23]([C:25]1[C:26]([CH3:35])=[C:27]([O:31][C:32](=[O:34])[CH3:33])[CH:28]=[CH:29][CH:30]=1)=[O:24].Cl.[Na+].[Cl-]>C1COCC1.O>[C:32]([O:31][C:27]1[C:26]([CH3:35])=[C:25]([CH:30]=[CH:29][CH:28]=1)[C:23]([NH:1][C@@H:2]([CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[C@H:3]([OH:7])[C:4]([OH:6])=[O:5])=[O:24])(=[O:34])[CH3:33]
Reactant: N[C@@H](Cc1ccccc1)[C@H](O)C(=O)O
Reactant: CC(=O)Oc1cccc(C(=O)Cl)c1C
Agent: Cl
Agent: [Cl-]
Agent: [Na+]
Solvent: O
Solvent: C1CCOC1
Solvent: CCN(CC)CC
Product: CC(=O)Oc1cccc(C(=O)N[C@@H](Cc2ccccc2)[C@H](O)C(=O)O)c1C
Temperature: 6 °C
Reaction time: 0.75 h
Yield: 92 %

Procedure:
(2S,3S)-3-Amino-2-hydroxy-4-phenyl-butyric acid (which can be prepared according to the method of Pedrosa et al., Tetrahedron Asymm. 2001, 12, 347; M. Shibasaki et al., Tetrahedron Lett. 1994, 35, 6123; and Ikunaka, M. et al. Tetrahedron Asymm. 2002, 13, 1201; 185 g; 948 mmol) was added to a 5-L flask and was suspended in THF (695 mL). H2O (695 mL) was poured in, followed by NEt3 (277 mL; 1990 mmol). After stirring for 45 min, the solution was cooled to 6° C. A solution of acetic acid 3-chlorocarbonyl-2-methyl-phenyl ester (201 g; 948 mmol) in THF (350 mL) was then added dropwise. One-half hour later, the pH was adjusted from 8.7 to 2.5 with 6 N HCl (˜170 mL). Solid NaCl (46 g) was added, the ice bath was then removed and the mixture was stirred vigorously while warming to room temperature. The mixture was transferred to 4-L separatory funnel, using 1:1 THF/H2O (50 mL) for the transfer, and the lower aqueous phase was then removed. The organic fraction was transferred to a 5-L distillation flask, and was then diluted with fresh THF (2.5 L). The solution was azeotropically dried and concentrated to a volume of 1.3 L by distillation of THF at one atmosphere. To complete the azeotropic drying, fresh THF (2.0 L) was added and the solution was concentrated to 1.85 L by distillation at one atmosphere and was then held at 55° C. n-Heptane (230 mL) was added dropwise via addition funnel and the solution was then immediately seeded. After crystallization had initiated, additional n-heptane (95 mL) was added dropwise. The resulting crystal slurry was stirred vigorously for 7 min. Additional n-heptane (1.52 L) was then added as a slow stream. The crystal slurry was then allowed to cool to room temperature slowly and stir overnight. The suspension was vacuum-filtered and the filter cake was then washed with 1:1 THF/n-heptane (700 mL). After drying in a vacuum oven at 45–50° C., 324 g (92%) of (2S,3S)-3-(3-acetoxy-2-methyl-benzoylamino)-2-hydroxy-4-phenyl-butyric acid was obtained as a crystalline solid contaminated with ˜7 mol % Et3N.HCl: mp=189–191° C., 1H NMR (300 MHz, DMSO-d6) δ 12.65 (br s, 1H), 3.80 (d, J=9.7 Hz, 1H), 7.16–7.30 (m, 6H), 7.07 (dd, J=1.1, 8.0 Hz, 1H), 7.00 (dd, J=1.1, 7.5 Hz), 4.40–4.52 (m, 1H), 4.09 (d, J=6.0 Hz, 1H), 2.92 (app dd, J=2.9, 13.9 Hz, 1H), 2.76 (app dd, J=11.4, 13.9 Hz, 1H), 2.29 (s, 3H), 1.80 (s, 3H); 13C NMR (75 MHz, DMSO-d6) δ 174.4, 169.3, 168.1, 149.5, 139.7, 139.4, 129.5, 128.3, 127.9, 126.5, 126.3, 124.8, 123.3, 73.2, 53.5, 35.4, 20.8, 12.6; MS (CI) m/z 372.1464 (372.1447 calcd for C20H22NO6, M+H+); elemental analysis calcd for C20H21NO6.0.07 Et3N.HCl: C, 64.34; H, 5.86; N, 3.95; Cl, 0.70; found: C, 64.27; H, 5.79; N, 3.96; Cl; 0.86.